An electrocardiograph (“ECG”) is a representation of the electrical signals generated by the heart muscle. Typical ECG devices derive one or more ECG waveforms by measuring small voltages that appear on pickup electrodes, or leads, placed on the surface of a patient's body. Electrocardiograph (ECG) machines typically include a display device, a plurality of electrodes, and control and signal conditioning circuitry. The electrodes are designed to be attached to the skin on the chest and limbs of a patient based on a 12-lead placement model. Generally, limb lead electrodes are placed on each arm and on the left leg, while precordial lead electrodes are placed on the left upper chest region over the heart in close proximity to the heart and at a location of strongest ventricular cardiac action potential signal strength. The display device presents a waveform representative of an electrical signal of each of the 12 leads, typically within a small window showing one or a small number of periodic intervals (e.g., approximately a single heartbeat cycle), based on detection of such signals by the control circuitry.
Because ECG devices typically present each of the 12 leads on a display, each waveform for each of the leads is typically restricted within a small region of the display. Typically, this is acceptable, since users of ECG devices can view a single heartbeat period within such a small region. However, in some cases, use of such small regions of a display is unacceptable. For example, it may be difficult, within such a small display region, to determine variations in a signal occurring over multiple heartbeat periods, such as drift of the electrical signal to a higher or lower voltage, which may indicate an issue with either the device or patient. In existing machines, to view an extended version of one of the waveforms, the user must navigate a series of configuration screens to reconfigure a display. To return to the screen displaying each of the 12 leads, the user must again navigate a series of configuration screens. Such reconfiguration of displays is time-intensive, and cumbersome.